A page back, someone mentioned having their headlight housing melt next to the projector on 01+ headlights. I had this problem too and have seen it on many other cars that had this done to them. The problem comes when the sun hits the glass projector and the beam gets focused into a death ray on the adjacent plastic housing. this causes melting, burning, flaking if the surface is any color other than chrome. Mazda placed metal shields around this area on the black chrome msm headlights to mitigate this issue, though sadly they arent large enough and even some factory msm units exhibit the melting. Perhaps this was added for the 05 model year, but Im not really able to find much information on that change. In any case, here is the melting on my headlights.
You can see why I would want to do something about it. So i took the headlight apart and stripped the paint and chrome off with oven cleaner to get a better look at the damage. here is the result. ugly, melty zig zags.
Lotus had this same problem with the elise, and used to replace the headlights under warranty. eventually they grew tired of that **** and tooled a ring to keep the light out of the projector. Here is what I did, in the same spirit.
sanded down the melted area:
Purchased a piece of 3" OD acrylic tube and carved out the housing to be a snug slip fit. A dremel would be nice for this, but go slow. you want this to fit without cracking the housing, but still be snug. determine the length of the tube so that the lens will fit without touching or interfering. use the same length for both sides, obviously.
cut your tube with a bandsaw, hacksaw, whatever. just make it straight. slide it into the housing and glue them together with IPS #4 adhesive for acrylic/polycarbonate plastics. The glue works by capillary action, and should come with a syringe for all you krokodil users. Paint the bitches, put the headlights back together. Your done. I used lenses from a set of ebay headlights because they are clearer and lack the flutes, making for a nicer looking light.
I think they look pretty good, and there is no way the sun can get to your projector to melt your housings now. light output is not changed in any way by doing this. Sorry if this was text and picture intensive, but hopefully I have provided a solution for a problem that some have been dealing with.